Soil compaction is an important procedure of precision seeding operation. In this paper, a precise downforce control system based\non fuzzy PID was proposed in order to improve the quality of the soil compaction and the accuracy of setting working parameters.\nThe conventional mechanism of seeders for soil compaction was optimised. The compressing spring of the compaction\nmechanism was replaced by a linear motor, which is actively controlled to adjust downforce in real time. A force sensor was\nconnected in series with the linear motor to detect the actual downforce from a press wheel acting on soil. The detected downforce\nwas employed as feedback for the fuzzy PID model. A slave real-time control system was constructed by using an STM32\nmicrocontroller. A user interface was designed for the portable master computer system based on the ForLinx embedded platform\nto facilitate the setting of target downforce and display the actual downforce in real time. Meanwhile, it was able to adjust the\nsystem for different operating requirements, such as soil stiffness, moisture, and crop species. Experiments were conducted on a\nsoil bin, and the results indicated that the active control system has better performance than the conventional passive system in\ndownforce control. The downforce was stable with a variance less than 2.6% under different conditions, and it was 8.11% less than\nthe conventional passive system.
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